Display device

ABSTRACT

A display device includes dots and a grayscale correction unit. Each dot among the dots includes a first pixel of a first color, a second pixel of a second color, and a third pixel of a third color. The grayscale correction unit is configured to generate corrected grayscale values for a target dot via application of weights to grayscale values of the target dot and grayscale values of neighboring dots of the target dot among the dots. The grayscale correction unit is configured to determine the weights based on the grayscale values of the target dot.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation-in-part of U.S. patent applicationSer. No. 17/155,554, filed Jan. 22, 2021, which is a continuation ofU.S. patent application Ser. No. 16/379,338, filed on Apr. 9, 2019, andclaims priority to Korean Patent Application Nos. 10-2018-0069109, filedon Jun. 15, 2018 and 10-2021-0116565 filed on Sep. 1, 2021, each ofwhich is hereby incorporated by reference for all purposes as if fullyset forth herein.

BACKGROUND Field

One or more embodiments generally relate to a display device.

Discussion

With the development of information technology, the importance ofdisplay devices, which are a connection medium between users andinformation, has been emphasized. In response, the use of displaydevices, such as a liquid crystal display device, an organic lightemitting display device, a plasma display device, and the like, has beenincreasing.

A display device typically writes a data voltage corresponding to eachpixel, and, thereby, causes each pixel to emit light. Each pixel emitslight with a luminance corresponding to the written data voltage. Thepixels of adjacent different single-color hues can be grouped and theunit of such a group can be defined as a dot. Each dot can representmore colors by a combination of the single-color hues. Pictures,characters, etc. of image frames can be expressed in dot units. It isnoted, however, that because the dots have a larger size than thepixels, aliasing in pictures, characters, etc. of the image framesexpressed in dot units can be viewed by a user.

The above information disclosed in this section is only forunderstanding the background of the inventive concepts, and, therefore,may contain information that does not form prior art.

SUMMARY

One or more embodiments provide a display device capable of displayingan image frame in which aliasing is relaxed with respect to variouspixel arrangement structures.

One or more embodiments provide a method of driving a display device,the method being capable of causing the display device to display animage frame in which aliasing is relaxed with respect to various pixelarrangement structures.

Additional aspects will be set forth in the detailed description whichfollows, and, in part, will be apparent from the disclosure, or may belearned by practice of the inventive concepts.

According to an embodiment, a display device includes dots and agrayscale correction unit. Each dot among the dots includes a firstpixel of a first color, a second pixel of a second color, and a thirdpixel of a third color. The grayscale correction unit is configured togenerate corrected grayscale values for a target dot via application ofweights to grayscale values of the target dot and grayscale values ofneighboring dots of the target dot among the dots. The grayscalecorrection unit is configured to determine the weights based on thegrayscale values of the target dot.

According to an embodiment, a method of driving a display deviceincludes: receiving grayscale values of a target dot and grayscalevalues of neighboring dots of the target dot among dots of the displaydevice, each dot among the dots including a first pixel of a firstcolor, a second pixel of a second color, and a third pixel of a thirdcolor; determining weights based on the grayscale values of the targetdot; and generating corrected grayscale values for the target dot byapplying the weights to the grayscale values of the target dot and thegrayscale values of the neighboring dots of the target dot.

The foregoing general description and the following detailed descriptionare illustrative and explanatory and are intended to provide furtherexplanation of the claimed subject matter.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a furtherunderstanding of the inventive concepts, and are incorporated in andconstitute a part of this specification, illustrate embodiments of theinventive concepts, and, together with the description, serve to explainprinciples of the inventive concepts.

FIG. 1 is a block diagram of a display device according to anembodiment.

FIG. 2 is a circuit diagram of a pixel of the display device of FIG. 1according to an embodiment.

FIG. 3 is a diagram for explaining a driving method of the pixel of FIG.2 according to an embodiment.

FIG. 4 is a block diagram of a display device according to anembodiment.

FIG. 5 is a circuit diagram of a pixel of the display device of FIG. 4according to an embodiment.

FIG. 6 is a diagram for explaining a driving method of the pixel of FIG.5 according to an embodiment.

FIG. 7 is a diagram for explaining a first image frame to whichanti-aliasing indicated in an RGB-stripe structure is not appliedaccording to an embodiment.

FIG. 8 is a diagram for explaining a second image frame to whichanti-aliasing indicated in an RGB-stripe structure is applied accordingto an embodiment.

FIG. 9 is an enlarged view of the first to third dots of FIG. 8according to an embodiment.

FIG. 10 is a diagram for explaining a case where a second image frame isdisplayed without correction in an S-stripe structure according to anembodiment.

FIG. 11 is a block diagram of a grayscale correction unit according toan embodiment.

FIG. 12 is a diagram for explaining a third image frame in which asecond image frame is corrected by the grayscale correction unitaccording to an embodiment.

FIG. 13 is a diagram for explaining a third image frame in which asecond image frame is corrected by the grayscale correction unitaccording to an embodiment.

FIG. 14 is an enlarged view of the fourth to sixth dots of FIG. 8according to an embodiment.

FIG. 15 is a diagram for explaining a case where a second image frame isdisplayed without correction in the S-stripe structure according to anembodiment.

FIG. 16 is a block diagram of a grayscale correction unit according toan embodiment.

FIG. 17 is a diagram for explaining a fourth image frame in which thesecond image frame is corrected by the grayscale correction unit of FIG.16 according to an embodiment.

FIG. 18 is a block diagram of a grayscale correction unit according toan embodiment.

FIG. 19 is an enlarged view of the seventh to tenth dots of FIG. 8according to an embodiment.

FIG. 20 is a diagram for explaining a case where a second image frame isdisplayed without correction in the S-stripe structure according to anembodiment.

FIG. 21 is a block diagram of a grayscale correction unit according toan embodiment.

FIG. 22 is a diagram for explaining a fifth image frame in which thesecond image frame is partially corrected by the grayscale correctionunit of FIG. 21 according to an embodiment.

FIG. 23 is a diagram for explaining a case where embodiments are appliedto the S-stripe structure which is different from those shown in FIGS. 1and 4.

FIGS. 24 and 25 are diagrams for explaining a grayscale correction unitaccording to an embodiment.

FIGS. 26 and 27 are diagrams for explaining a grayscale correction unitaccording to an embodiment.

FIGS. 28 to 30 are diagrams for explaining variously set weights when asaturation value is a minimum value according to various embodiments.

FIGS. 31 to 34 are diagrams for explaining structures of dots accordingto various embodiments.

DETAILED DESCRIPTION OF SOME EMBODIMENTS

In the following description, for the purposes of explanation, numerousspecific details are set forth in order to provide a thoroughunderstanding of various embodiments. As used herein, the terms“embodiments” and “implementations” may be used interchangeably and arenon-limiting examples employing one or more of the inventive conceptsdisclosed herein. It is apparent, however, that various embodiments maybe practiced without these specific details or with one or moreequivalent arrangements. In other instances, well-known structures anddevices are shown in block diagram form to avoid unnecessarily obscuringvarious embodiments. Further, various embodiments may be different, butdo not have to be exclusive. For example, specific shapes,configurations, and characteristics of an embodiment may be used orimplemented in another embodiment without departing from the inventiveconcepts.

Unless otherwise specified, the illustrated embodiments are to beunderstood as providing example features of varying detail of someembodiments. Therefore, unless otherwise specified, the features,components, modules, layers, films, panels, regions, aspects, etc.(hereinafter individually or collectively referred to as an “element” or“elements”), of the various illustrations may be otherwise combined,separated, interchanged, and/or rearranged without departing from theinventive concepts.

The use of cross-hatching and/or shading in the accompanying drawings isgenerally provided to clarify boundaries between adjacent elements. Assuch, neither the presence nor the absence of cross-hatching or shadingconveys or indicates any preference or requirement for particularmaterials, material properties, dimensions, proportions, commonalitiesbetween illustrated elements, and/or any other characteristic,attribute, property, etc., of the elements, unless specified. Further,in the accompanying drawings, the size and relative sizes of elementsmay be exaggerated for clarity and/or descriptive purposes. As such, thesizes and relative sizes of the respective elements are not necessarilylimited to the sizes and relative sizes shown in the drawings. When anembodiment may be implemented differently, a specific process order maybe performed differently from the described order. For example, twoconsecutively described processes may be performed substantially at thesame time or performed in an order opposite to the described order.Also, like reference numerals denote like elements.

When an element, such as a layer, is referred to as being “on,”“connected to,” or “coupled to” another element, it may be directly on,connected to, or coupled to the other element or intervening elementsmay be present. When, however, an element is referred to as being“directly on,” “directly connected to,” or “directly coupled to” anotherelement, there are no intervening elements present. Other terms and/orphrases used to describe a relationship between elements should beinterpreted in a like fashion, e.g., “between” versus “directlybetween,” “adjacent” versus “directly adjacent,” “on” versus “directlyon,” etc. Further, the term “connected” may refer to physical,electrical, and/or fluid connection. In addition, the DR1-axis, theDR2-axis, and the DR3-axis are not limited to three axes of arectangular coordinate system, and may be interpreted in a broadersense. For example, the DR1-axis, the DR2-axis, and the DR3-axis may beperpendicular to one another, or may represent different directions thatare not perpendicular to one another. For the purposes of thisdisclosure, “at least one of X, Y, and Z” and “at least one selectedfrom the group consisting of X, Y, and Z” may be construed as X only, Yonly, Z only, or any combination of two or more of X, Y, and Z, such as,for instance, XYZ, XYY, YZ, and ZZ. As used herein, the term “and/or”includes any and all combinations of one or more of the associatedlisted items.

Although the terms “first,” “second,” etc. may be used herein todescribe various elements, these elements should not be limited by theseterms. These terms are used to distinguish one element from anotherelement. Thus, a first element discussed below could be termed a secondelement without departing from the teachings of the disclosure.

Spatially relative terms, such as “beneath,” “below,” “under,” “lower,”“above,” “upper,” “over,” “higher,” “side” (e.g., as in “sidewall”), andthe like, may be used herein for descriptive purposes, and, thereby, todescribe one element's relationship to another element(s) as illustratedin the drawings. Spatially relative terms are intended to encompassdifferent orientations of an apparatus in use, operation, and/ormanufacture in addition to the orientation depicted in the drawings. Forexample, if the apparatus in the drawings is turned over, elementsdescribed as “below” or “beneath” other elements or features would thenbe oriented “above” the other elements or features. Thus, the term“below” can encompass both an orientation of above and below.Furthermore, the apparatus may be otherwise oriented (e.g., rotated 90degrees or at other orientations), and, as such, the spatially relativedescriptors used herein interpreted accordingly.

The terminology used herein is for the purpose of describing someembodiments and is not intended to be limiting. As used herein, thesingular forms, “a,” “an,” and “the” are intended to include the pluralforms as well, unless the context clearly indicates otherwise. Moreover,the terms “comprises,” “comprising,” “includes,” and/or “including,”when used in this specification, specify the presence of statedfeatures, integers, steps, operations, elements, components, and/orgroups thereof, but do not preclude the presence or addition of one ormore other features, integers, steps, operations, elements, components,and/or groups thereof. It is also noted that, as used herein, the terms“substantially,” “about,” and other similar terms, are used as terms ofapproximation and not as terms of degree, and, as such, are utilized toaccount for inherent deviations in measured, calculated, and/or providedvalues that would be recognized by one of ordinary skill in the art.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure is a part. Terms,such as those defined in commonly used dictionaries, should beinterpreted as having a meaning that is consistent with their meaning inthe context of the relevant art and will not be interpreted in anidealized or overly formal sense, unless expressly so defined herein.

As customary in the field, some embodiments are described andillustrated in the accompanying drawings in terms of functional blocks,units, and/or modules. Those skilled in the art will appreciate thatthese blocks, units, and/or modules are physically implemented byelectronic (or optical) circuits, such as logic circuits, discretecomponents, microprocessors, hard-wired circuits, memory elements,wiring connections, and the like, which may be formed usingsemiconductor-based fabrication techniques or other manufacturingtechnologies. In the case of the blocks, units, and/or modules beingimplemented by microprocessors or other similar hardware, they may beprogrammed and controlled using software (e.g., microcode) to performvarious functions discussed herein and may optionally be driven byfirmware and/or software. It is also contemplated that each block, unit,and/or module may be implemented by dedicated hardware, or as acombination of dedicated hardware to perform some functions and aprocessor (e.g., one or more programmed microprocessors and associatedcircuitry) to perform other functions. Also, each block, unit, and/ormodule of some embodiments may be physically separated into two or moreinteracting and discrete blocks, units, and/or modules without departingfrom the inventive concepts. Further, the blocks, units, and/or modulesof some embodiments may be physically combined into more complex blocks,units, and/or modules without departing from the inventive concepts.

Hereinafter, various embodiments will be explained in detail withreference to the accompanying drawings.

FIG. 1 is a block diagram of a display device 10 according to anembodiment.

Referring to FIG. 1, the display device 10 according to an embodimentmay include a timing controller 11, a data driver 12, a scan driver 13,a pixel unit 14, and a grayscale correction unit 15.

A processor 9 may be a general-purpose processing device. For example,the processor 9 may be an application processor (AP), a centralprocessing unit (CPU), a graphics processing unit (GPU), a microcontroller unit (MCU), or another host system.

The processor 9 may provide control signals for displaying an imageframe and grayscale values for each pixel to the timing controller 11.The control signals may include, for example, a data enable signal, avertical synchronization signal, a horizontal synchronization signal, atarget maximum luminance, and/or the like.

The timing controller 11 may provide a clock signal, a scan startsignal, and the like to the scan driver 13 so as to conform tospecifications of the scan driver 13 based on the received controlsignals. In addition, the timing controller 11 may provide the datadriver 12 with grayscale values and control signals that have beenmodified or maintained to conform to specifications of the data driver12 based on the received grayscale values and control signals.

The data driver 12 may generate data voltages to be provided to datalines D1, D2, D3, . . . , Dn using the grayscale values and the controlsignals received from the timing controller 11. For example, the datavoltages generated in units of pixel rows may be simultaneously appliedto the data lines D1 to Dn according to output control signals includedin the control signals.

The scan driver 13 may receive the control signals such as a clocksignal, a scan start signal, and the like from the timing controller 11and may generate scan signals to be supplied to the scan lines S1, S2,S3, . . . , and Sm. For example, the scan driver 13 may sequentiallyprovide turn-on level scan signals to the scan lines S1 to Sn. Forexample, the scan driver 13 may be configured in the form of a shiftregister and may generate scan signals in a manner that sequentiallytransfers the scan start signal to the next stage circuit under thecontrol of the clock signal.

The pixel unit 14 may include pixels, such as pixels PX1, PX2, and PX3.Each pixel, such as pixels PX1, PX2, and PX3, may be connected to acorresponding data line and a corresponding scan line. For example, whenthe data voltages for one pixel row are applied to the data lines D1 toDn from the data driver 12, the data voltages may be written to thepixel row connected to the scan line supplied with the scan signal of aturn-on level from the scan driver 13. This driving method will bedescribed in more detail with reference to FIGS. 2 and 3.

Each pixel, such as pixels PX1, PX2, and PX3, may emit light of a singlecolor. For example, a first pixel PX1 may emit light of a first colorC1, a second pixel PX2 may emit light of a second color C2, and a thirdpixel PX3 may emit light of a third color C3. The color of each pixelmay be determined by the size of a bandgap of an organic material of anorganic light emitting diode OLED1 of FIG. 2 to be described below. Thefirst, second, and third colors C1, C2, and C3 may be variously setaccording to the design of the display device 10. For example, thefirst, second, and third colors C1, C2, and C3 may correspond to red,green, and blue, respectively. The first, second, and third colors C1,C2, and C3 may correspond to green, red, and blue, respectively. Thefirst, second, and third colors C1, C2, and C3 may correspond to green,blue, and red, respectively. The first, second, and third colors C1, C2,and C3 may correspond to blue, green, and red, respectively. The first,second, and third colors C1, C2, and C3 may correspond to red, blue, andgreen, respectively. In addition, the first, second, and third colorsC1, C2, and C3 may correspond to blue, red, and green, respectively. Inother embodiments, the first, second, and third colors C1, C2, and C3may optionally correspond to cyan, magenta, and yellow. In still otherembodiments, alternative or additional colors may be utilized.

The third pixel PX3 may be located in a first direction DR1 from thefirst pixel PX1 and the second pixel PX2, and the first pixel PX1 may belocated in a second direction DR2 from the second pixel PX2.Hereinafter, positions of the pixels PX1, PX2, and PX3 will be describedwith reference to the light emitting regions of the pixels PX1, PX2, andPX3. Circuit regions of the pixels PX1, PX2, and PX3 may not coincidewith the corresponding light emitting regions.

A first dot DT1 may be defined as a group of the first pixel PX1, thesecond pixel PX2, and the third pixel PX3. Such a pixel layout structuremay be referred to as an S-stripe structure. Unlike the RGB-stripestructure to be described below, the S-stripe structure is advantageousin securing an aperture ratio of a fine metal mask (FMM) used in one ormore deposition processes of the organic light emitting diode. Forinstance, the interval between the pixels of the same color can beincreased.

The grayscale correction unit 15 may generate a first correctedgrayscale value and a second corrected grayscale value based on a firstgrayscale value and a second grayscale value for the first pixel PX1 andthe second pixel PX2 when the first dot DT1 is determined as an edge ofan object included in the image frame. At this time, the timingcontroller 11 may provide the first corrected grayscale value to thefirst pixel PX1, the second corrected grayscale value to the secondpixel PX2, and a third grayscale value not corrected to the third pixelPX3. As such, the data driver 12 may supply a first data voltagecorresponding to the first corrected grayscale value to the first pixelPX1, a second data voltage corresponding to the second correctedgrayscale value to the second pixel PX2, and a third data voltagecorresponding to the third grayscale value to the third pixel PX3.Various embodiments of the grayscale correction unit 15 will bedescribed below with reference to FIGS. 11 to 18.

In one embodiment, the grayscale correction unit 15 and the timingcontroller 11 may exist as independent individual chips. In anotherembodiment, the grayscale correction unit 15 and the timing controller11 may exist as an integrated single chip. For example, the grayscalecorrection unit 15 and the timing controller 11 may exist as a singleintegrated circuit (IC).

Hereinafter, the display device 10 will be described on the basis of anorganic light emitting display device. However, those skilled in the artwill understand that if a pixel circuit of FIGS. 2 and 3 is replaced,the display device 10 can also be applied to other display devices, suchas a liquid crystal display device.

FIG. 2 is a circuit diagram of a pixel of the display device of FIG. 1according to an embodiment. FIG. 3 is a diagram for explaining a drivingmethod of the pixel of FIG. 2 according to an embodiment.

Referring to FIG. 2, a circuit structure of an exemplary pixel PXij isshown. It is assumed that the pixel PXij is connected to an arbitraryi-th scan line Si and a j-th data line Dj. The first, second and thirdpixels PX1, PX2, and PX3 may include a circuit structure of the pixelPxij.

The pixel PXij may include a plurality of transistors T1 and T2, astorage capacitor Cst1, and an organic light emitting diode OLED1.Although the transistors T1 and T2 are shown as P-type transistors,those skilled in the art will recognize that a pixel circuit having thesame function may be formed using N-type transistors or a combination ofP-type and N-type transistors.

The transistor T2 may include a gate electrode connected to the scanline Si, one electrode connected to the data line Dj, and its otherelectrode connected to a gate electrode of the transistor T1. Thetransistor T2 may be referred to as a switching transistor, a scantransistor, or the like.

The transistor T1 may include a gate electrode connected to the otherelectrode of the transistor T2, one electrode connected to a first powersupply voltage line ELVDD and its other electrode connected to an anodeelectrode of the organic light emitting diode OLED1. The transistor T1may be referred to as a driving transistor.

The storage capacitor Cst1 may connect the one electrode and the gateelectrode of the transistor T1.

The organic light emitting diode OLED1 may include an anode electrodeconnected to the other electrode of the transistor T1 and a cathodeelectrode connected to a second power supply voltage line ELVSS.

When a scan signal of a turn-on level (e.g., a low level) is supplied tothe gate electrode of the transistor T2 through the scan line Si, thetransistor T2 may connect the data line Dj and one electrode of thestorage capacitor Cst1. As such, a voltage value corresponding to thedifference between a data voltage DATAij applied through the data lineDj and the first power supply voltage is written to the storagecapacitor Cst1. The transistor T1 may cause a driving current determinedaccording to the voltage value written to the storage capacitor Cst1 toflow from the first power supply voltage line ELVDD to the second powersupply voltage line ELVSS. The organic light emitting diode OLED1 mayemit light with the luminance corresponding to the amount of the drivingcurrent.

FIG. 4 is a block diagram of a display device 10′ according to anembodiment.

Referring to FIG. 4, the display device 10′ may include a timingcontroller 11′, a data driver 12′, a scan driver 13′, a pixel unit 14′,a grayscale correction unit 15′, and a light emitting driver 16′.

Compared with the exemplary embodiment(s) described in association withFIG. 1, the display device 10′ may further include the light emittingdriver 16′. The other elements of the display device 10′ other than thelight emitting driver 16′ may be the same as or similar to those of thedisplay device 10 of FIG. 1, and thus, duplicate descriptions areomitted.

The light emitting driver 16′ may supply light emitting signals fordetermining light emitting periods of the pixels, such as pixels PX1′,PX2′, and PX3′, of the pixel unit 14′ to light emitting lines E1, E2,E3, . . . , Em′. The light emitting driver 16′ may supply the lightemitting signals of a turn-off level to the light emitting lines E1 toEm′ in a period in which the corresponding scan signal of the turn-onlevel is supplied. According to one embodiment, the light emittingdriver 16′ may be of a sequential light emitting type. The lightemitting driver 16′ may be configured in the form of a shift registerand may generate the light emitting signals by sequentially transmittinglight emitting start signals to the next stage circuit under the controlof a clock signal. According to another embodiment, the light emittingdriver 16′ may be a simultaneous light emitting type in which all thepixel rows are simultaneously emitted.

FIG. 5 is a circuit diagram of a pixel of the display device of FIG. 4according to an embodiment.

Referring to FIG. 5, a pixel PXij′ may include transistors M1, M2, M3,M4, M5, M6, and M7, a storage capacitor Cst2, and an organic lightemitting diode OLED2.

The storage capacitor Cst2 may include one electrode connected to thefirst power supply voltage line ELVDD and its other electrode connectedto a gate electrode of the transistor M1.

The transistor M1 may include one electrode connected to the otherelectrode of the transistor M5, its other electrode connected to the oneelectrode of the transistor M6, and a gate electrode connected to theother electrode of the storage capacitor Cst2. The transistor M1 may bereferred to as a driving transistor. The transistor M1 may determine theamount of driving current flowing between the first power supply voltageline ELVDD and the second power supply voltage line ELVSS according tothe potential difference between its gate electrode and its sourceelectrode.

The transistor M2 may include one electrode connected to the data lineDj, its other electrode connected to the one electrode of the transistorM1, and a gate electrode connected to the current scan line Si. Thetransistor M2 may be referred to as a switching transistor, a scantransistor, or the like. The transistor M2 may transfer the data voltageof the data line Dj to the pixel PXij when a scan signal of a turn-onlevel is applied to the current scan line Si.

The transistor M3 may include one electrode connected to the otherelectrode of the transistor M1, its other electrode connected to thegate electrode of the transistor M1, and a gate electrode connected tothe current scan line Si. The transistor M3 may connect the transistorM1 in a diode form when a scan signal of a turn-on level is applied tothe current scan line Si.

The transistor M4 may include one electrode connected to the gateelectrode of the transistor M1, its other electrode connected to aninitialization voltage line VINT, and a gate electrode connected to aprevious scan line S(i−1). In another embodiment, the gate electrode ofthe transistor M4 may be connected to another scan line. The transistorM4 may transfer an initialization voltage of the initialization voltageline VINT to the gate electrode of the transistor M1 to initialize theamount of charge of the gate electrode of the transistor M1 when thescan signal of the turn-on level is applied to the previous scan lineS(i−1).

The transistor M5 may include one electrode connected to the first powersupply voltage line ELVDD, its other electrode connected to the oneelectrode of the transistor M1, and a gate electrode connected to alight emitting line Ei. The transistor M6 may include one electrodeconnected to the other electrode of the transistor M1, its otherelectrode connected to an anode electrode of the organic light emittingdiode OLED2, and a gate electrode connected to the light emitting lineEi. The transistors M5 and M6 may be referred to as a light emittingtransistor. The transistors M5 and M6 may form a driving current pathbetween the first power supply voltage line ELVDD and the second powersupply voltage line ELVSS when a light emitting signal of a turn-onlevel is applied so that the organic light emitting diode OELD2 emitslight.

The transistor M7 may include one electrode connected to the anodeelectrode of the organic light emitting diode OLED2, the other electrodeconnected to the initialization voltage line VINT, and a gate electrodeconnected to the current scan line Si. In another embodiment, the gateelectrode of the transistor M7 may be connected to another scan line.For example, the gate electrode of the transistor M7 may be connected tothe next scan line (an (i+1)-th scan line) or a subsequent scan line.The transistor M7 may transfer the initialization voltage to the anodeelectrode of the organic light emitting diode OLED2 to initialize theamount of charge accumulated in the organic light emitting diode OELD2when the scan signal of the turn-on level is applied to the current scanline Si.

The organic light emitting diode OELD2 may include an anode electrodeconnected to the other electrode of the transistor M6 and a cathodeelectrode connected to the second power supply voltage line ELVSS.

FIG. 6 is a diagram for explaining a driving method of the pixel of FIG.5 according to an embodiment.

First, a data voltage DATA(i−1)j for a previous pixel row may be appliedto the data line Dj and the scan signal of the turn-on level (e.g., alow level) may be applied to the previous scan line S(i−1).

Since the scan signal of the turn-off level (e.g., a high level) isapplied to the current scan line Si, the transistor M2 may be turned offand the data voltage for the previous pixel row (DATA(i−1)j) may not betransferred to the pixel PXij.

At this time, since the transistor M4 is turned on, the initializationvoltage may be applied to the gate electrode of the transistor M1 toinitialize the amount of charge. Since a light emitting control signalof a turn-off level is applied to the light emitting line Ei, thetransistors M5 and M6 may be turned off and unnecessary light emissionof the organic light emitting diode OLED2 may be prevented during theinitialization voltage application process.

Next, a data voltage DATAij for a current pixel row may be applied tothe data line Dj and the scan signal of the turn-on level may be appliedto the current scan line Si. As a result, the transistors M2, M1, and M3may be turned on, and the data line Dj and the gate electrode of thetransistor M1 may be electrically connected. As such, the data voltageDATAij may be applied to the other electrode of the storage capacitorCst2 and the storage capacitor Cst2 may accumulate the amount of chargecorresponding to the difference between the voltage of the first powersupply voltage line ELVDD and the data voltage DATAij.

At this time, since the transistor M7 is turned on, the anode electrodeof the organic light emitting diode OLED2 may be connected to theinitialization voltage line VINT, and the organic light emitting diodeOLED2 may be pre-charged or initialized with the amount of chargecorresponding to the voltage difference between the initializationvoltage and the voltage of the second power supply voltage line ELVSS.

Thereafter, the transistors M5 and M6 may be turned on as the lightemitting signal of the turn-on level is applied to the light emittingline Ei, the amount of the driving current passing through thetransistor M1 may be adjusted according to the amount of charge storedin the storage capacitor Cst2, and the driving current may flow throughthe organic light emitting diode OLED2. The organic light emitting diodeOLED2 may emit light until the light emitting signal of the turn-offlevel is applied to the light emitting line Ei.

FIG. 7 is a diagram for explaining a first image frame IMF1 to whichanti-aliasing indicated in the RGB-stripe structure is not appliedaccording to an embodiment.

The pixel unit for displaying the first image frame IMF1 of FIG. 7 mayhave an RGB-stripe structure unlike the embodiments described inassociation with FIGS. 1 and 4.

Referring to FIG. 7, each of dots, such as dots DT1 a, DT2 a, DT3 a, DT4a, DT5 a, DT6 a, DT1 a′, DT2 a′, DT3 a′, DT4 a′, DT5 a′, and DT6 a′, mayinclude a pixel of the first color C1, a pixel of the second color C2,and a pixel of the third color C3 sequentially positioned in the firstdirection DR1. This pixel arrangement structure may be referred to as anRGB-stripe structure.

The processor 9 may provide the timing controller 11 with the grayscalevalues corresponding to the pixels so that the pixels have the desiredluminance level for the first image frame IMF1. For example, when agrayscale value is represented by 8 bits, 256 (=2⁵) grayscale levels canbe expressed in each pixel. The number of bits representing eachgrayscale value may be varied according to the specification of theprocessor 9 or the display device 10.

The processor 9 may provide grayscale values for the pixels to thetiming controller 11 to display a character in the first image frameIMF1. Thus, the dots, such as dots DT1 a, DT2 a, DT6 a, DT3 a′, DT1 a′,and DT5 a′, constituting the character can display black color and thedots, such as dots DT3 a, DT4 a, DT6 a, DT2 a′, DT3 a′, and DT6 a′, thatdo not constitute the character can display white color.

For example, the processor 9 may provide all the grayscale values of thepixels included in the black dots as “0” and the grayscale values of thepixels included in the white dots as “255”.

However, because the dots have a larger size than the pixels, aliasingin the first image frame IMF1 in which a character is expressed in dotunits may be viewed by the user.

FIG. 8 is a diagram for explaining a second image frame to whichanti-aliasing indicated in the RGB-stripe structure is applied accordingto an embodiment. FIG. 9 is an enlarged view of the first to third dotsof FIG. 8 according to an embodiment.

The pixel unit for displaying a second image frame IMF2 of FIG. 8 mayhave an RGB-stripe structure unlike the embodiments of FIGS. 1 and 4.The structure of the pixel unit of FIG. 8 may be the same as that of thepixel unit of FIG. 7.

Referring FIG. 8, each of dots, such as dots DT1 b, DT2 b, DT3 b, DT4 b,DT5 b, DT6 b, DT1 b′, DT2 b′, DT3 b′, DT4 b′, DT5 b′, and DT6 b′, mayinclude a pixel of the first color C1, a pixel of the second color C2,and a pixel of the third color C3 sequentially positioned in the firstdirection DR1.

The processor 9 may provide grayscale values for the second image frameIMF2 applied with anti-aliasing to the character of the first imageframe IMF1 to the timing controller 11. The font of the character of thesecond image frame IMF2 of FIG. 8 may be different from that of thecharacter of the first image frame IMF1 of FIG. 7. In one embodiment,the processor 9 does not convert the character of the first image frameIMF1 into the character of the second image frame IMF2 through aseparate process and can include the character of the specific fontwhose grayscale values are determined so that the anti-aliasing effectappears in the second image frame IMF2. For example, a clear-type fontprovided in Windows™ may correspond to this embodiment. In anotherembodiment, the processor 9 may transform the grayscale values of thecharacter of the first image frame IMF1 through an anti-aliasingalgorithm to generate grayscale values of the character of the secondimage frame IMF2.

The processor 9 may provide grayscale values to the timing controller 11so that the pixels of the dots DT1 b and DT1 b′ constituting the edge ofthe character have sequentially rising or falling luminance levels.Here, the edge of the character may mean an edge located in the firstdirection DR1 or an edge located in a direction opposite to the firstdirection DR1 with respect to the character.

For example, referring to FIG. 9, the first dot DT1 b constituting theedge of the character in the direction opposite to the first directionDR1 with respect to the character may include the first, second, andthird pixels PX1 b, PX2 b and PX3 b, and the processor 9 may providefirst to third grayscale values so that the first, second, and thirdpixels PX1 b, PX2 b, and PX3 b have sequentially falling luminancelevels. For instance, the first to third grayscale values are differentfrom each other, and the second grayscale value may correspond to avalue between the first grayscale value and the third grayscale value.For example, the processor 9 may provide the first grayscale value of“200” to the first pixel PX1 b, the second grayscale value of “100” tothe second pixel PX2 b, and the third grayscale value of “50” to thethird pixel PX3 b.

At this time, the processor 9 may provide the grayscale value of “255”to the pixels of the third dot DT3 b located in the direction oppositeto the first direction DR1 of the first dot DT1 b and may provide thegrayscale value of “0” to the pixels of the second dot DT2 b located inthe first direction DR1 of the first dot DT1 b.

Similarly, the first dot DT1 b′ constituting the edge of the characterin the first direction DR1 with respect to the character may include thefirst to third pixels, and the processor 9 may provide first to thirdgrayscale values so that the first to third pixels have sequentiallyrising luminance levels. For instance, the first to third grayscalevalues may be different from each other, and the second grayscale valuemay correspond to a value between the first grayscale value and thethird grayscale value. For example, the processor 9 may provide thefirst grayscale value of “50” to the first pixel, the second grayscalevalue of “100” to the second pixel, and the third grayscale value of“200” to the third pixel.

At this time, the processor 9 may provide the grayscale value of “0” tothe pixels of the third dot DT3 b′ located in the direction opposite tothe first direction DR1 of the first dot DT1 b′ and may provide thegrayscale value of “255” to the pixels of the second dot DT2 b′ locatedin the first direction DR1 of the first dot DT1 b′.

Therefore, the user can observe and perceive the character included inthe second image frame IMF2 of FIG. 8 more smoothly and clearly than thecharacter included in the first image frame IMF1 of FIG. 7.

FIG. 10 is a diagram for explaining a case where the second image frameis displayed without correction in the S-stripe structure according toan embodiment.

Referring to FIG. 10, the case where the grayscale values of the secondimage frame IMF2 provided by the processor 9 are applied to the pixelunit 14 of the display device 10 of FIG. 1 without correction is shown.

Since the second image frame IMF2 provided by the processor 9 is basedon the RGB-stripe structure, when the grayscale values of the secondimage frame IMF2 are directly applied to the pixel unit 14 of thedisplay device 10 having the S-stripe structure, the desiredanti-aliasing effect cannot be obtained.

In the above example, in the second image frame IMF2, the firstgrayscale value of the first pixel PX1 b may be provided as “200”, thesecond grayscale value of the second pixel PX2 b may be provided as“100”, and the third grayscale value of the third pixel PX3 b may beprovided as “50”. In this case, the first grayscale value of the firstpixel PX1 located in the same column in the second direction DR2 maybecome “200” and the second grayscale value of the second pixel PX2 maybecome “100” so that the displayed character may have a serrated edge.Therefore, the first grayscale value and the second grayscale value mayrequire correction. However, since the relative location of the thirdpixel PX3 in the first dot DT1 of the S-stripe structure is the same asor similar to that of the third pixel PX3 b in the first dot DT1 b ofthe RGB-stripe structure, correction of the third grayscale value may beunnecessary.

FIG. 11 is a block diagram of a grayscale correction unit 15 a accordingto an embodiment. FIG. 12 is a diagram for explaining a third imageframe in which the second image frame is corrected by the grayscalecorrection unit 15 a of FIG. 11 according to an embodiment.

Referring to FIG. 11, the grayscale correction unit 15 a of the firstembodiment may include a first dot detection unit 110 and a first dotconversion unit 120.

The first dot detection unit 110 may output a first detection signal 1DSwhen an edge value of the first dot DT1 calculated based on grayscalevalues G11, G12, G13, G21, G22, G23, G31, G32, and G33 of the first,second, and third dots DT1, DT2, and DT3 is equal to or larger than thethreshold value.

It is typically necessary to detect which dots constitute the edge ofthe character before performing the correction, unless the timingcontroller 11 receives information on the pixels constituting thecharacter from the processor 9 or other source. However, since thedisplay device 10 cannot discriminate whether the detected dot is theedge of the figure or the edge of the character, unless the displaydevice 10 receives additional information from the processor 9determination of the edge of the character may be difficult.Hereinafter, a process of detecting the edge of an object by the firstdot detection unit 110 will be described.

In the following description, the first dot detection unit 110 maydetect whether or not the target dot corresponds to the edge dot in dotunits. For example, when there are three pixels constituting the dot,the average value of the grayscale values for the three pixels can beset as the value of the dot. At this time, the grayscale values of eachpixel may be multiplied by a weight value according to an embodiment.Hereinafter, for the sake of convenience of explanation, the averagevalue of the grayscale values constituting the dot will be described asthe value of the dot by setting the weight value for the grayscale valueof each pixel to 1.

According to one embodiment, the first dot detection unit 110 may applya Prewitt mask of a single row in which the first direction DR1 is therow direction to the first, second, and third dots DT1, DT2, and DT3 tocalculate the edge value of the dot DT1. For example, the Prewitt maskof the single row may correspond to Equation 1. In the case of using thePrewitt mask of the single row, the existing line buffer of the timingcontroller 11 can be used. Therefore, a separate line buffer may beunnecessary, and as such, cost reduction may be possible.

[−1 0 1]  Equation 1

In Equation 1, “0” in the first row and the second column can bemultiplied by the value of a discrimination target dot, “−1” in thefirst row and the first column can be multiplied by the value of the dotadjacent to a direction opposite to the first direction DR1 of thediscrimination target dot, and “1” in the first row and the third columncan be multiplied by the value of the dot adjacent to the firstdirection DR1 of the discrimination target dot. The sum of themultiplied values may correspond to the edge value of the discriminationtarget dot. Here, when the edge value is a negative number, it may meanthat the grayscale value falls in the first direction DR1 with thediscrimination target dot as a boundary. Also, when the edge value is apositive number, it may mean that the grayscale value rises in the firstdirection DR1 with the discrimination target dot as a boundary.

For example, referring to FIGS. 8, 9, and 10, a case where the third dotDT3 corresponds to the discrimination target dot will be described.Since grayscale values G31, G32, and G33 of the third dot DT3 are all“255”, a value of the third dot DT3 may be “255”. A value of the dotadjacent to a direction opposite to the first direction DR1 of the thirddot DT3 may be “255”. Since the grayscale values G11, G12, and G13 ofthe first dot DT1 adjacent to the first direction DR1 of the third dotDT3 are “200”, “100”, and “50”, respectively, a value of the first dotDT1 may be “116”. For convenience, the fractional part is clipped.Therefore, when Equation 1 is applied with the third dot DT3 as thediscrimination target dot, the edge value of the third dot DT3 maybecome “−139” by the following Equation 2.

255*(−1)+255*0+116*1=−139   Equation 2

For example, referring to FIGS. 8 and 9, a case where the first dot DT1corresponds to the discrimination target dot will be described. Asdescribed above, the value of the first dot DT1 may be “116” and thevalue of the third dot DT3 may be “255”. Since grayscale values G21,G22, and G23 of the second dot DT2 are “0”, a value of the second dotDT2 may be “0”. Therefore, when Equation 1 is applied with the first dotDT1 as the discrimination target dot, the edge value of the first dotDT1 may become “−255” by the following Equation 3.

255*(−1)+116*0+0*1=−255   Equation 3

For example, referring to FIGS. 8 and 9, a case where the second dot DT2corresponds to the discrimination target dot will be described. Asdescribed above, the value of the second dot DT2 may be “0”, the valueof the first dot DT1 may be “116”, and a value of the dot adjacent tothe first direction DR1 of the second dot DT2 may be “116”. Therefore,when Equation 1 is applied with the second dot DT2 as the discriminationtarget dot, the edge value of the second dot DT2 may become “0” by thefollowing Equation 4.

116*(−1)+0*0+116*1=0   Equation 4

According to one embodiment, when the edge value of the discriminationtarget dot is equal to or greater than the threshold value, the firstdot detection unit 110 can determine that the discrimination target dotcorresponds to the edge dot, and output the first detection signal DS.

For example, the threshold value can be predetermined as 70% of themaximum value of the dot value. In this case, if the maximum value ofthe dot value is 255, the threshold value may become 178. Referring toEquations 2, 3, and 4, the absolute value of the edge value of only thefirst dot DT1 of the dots DT3, DT1, and DT2 may exceed 178. Therefore,the first dot detection unit 110 can output the first detection signal1DS only for the first dot DT1 of the dots DT3, DT1, and DT2.

The Prewitt mask of a single row may be set as the following Equation 5.

[1 0 −1]  Equation 5

The sign of the calculated edge value of the mask of Equation 5 can bereversed to that of the mask of Equation 1.

In another embodiment, the first dot detection unit 110 may calculatethe edge value of the discrimination target dot using a Prewitt mask ora Sobel mask of a plurality of rows in which the first direction DR1 isthe row direction and the second direction DR2 is the column direction.

For example, the Prewitt mask of the plurality of rows may correspond toEquation 6 or 7.

$\begin{matrix}\begin{bmatrix}{- 1} & 0 & 1 \\{- 1} & 0 & 1 \\{- 1} & 0 & 1\end{bmatrix} & {{Equation}\mspace{14mu} 6} \\\begin{bmatrix}1 & 0 & {- 1} \\1 & 0 & {- 1} \\1 & 0 & {- 1}\end{bmatrix} & {{Equation}\mspace{14mu} 7}\end{matrix}$

According to Equations 6 and 7, when calculating the edge value of thefirst dot DT1, three dots in the previous row and three dots in the nextrow of the first, second, and third dots DT1, DT2, and DT3 may furtherbe considered. The calculation method may be similar to the case ofusing the Prewitt mask of the single row, and thus, duplicatedescriptions thereof will be omitted.

For example, a Sobel mask of a plurality of rows may correspond toEquation 8 or 9.

$\begin{matrix}\begin{bmatrix}{- 1} & 0 & 1 \\{- 2} & 0 & 2 \\{- 1} & 0 & 1\end{bmatrix} & {{Equation}\mspace{14mu} 8} \\\begin{bmatrix}1 & 0 & {- 1} \\2 & 0 & {- 2} \\1 & 0 & {- 1}\end{bmatrix} & {{Equation}\mspace{14mu} 9}\end{matrix}$

The calculation method may be similar to the case of using the Prewittmask of the plurality of rows, and thus, duplicate descriptions thereofwill be omitted.

The first dot conversion unit 120 may convert the first grayscale valueG11 into a first corrected grayscale value G11′ and may convert thesecond grayscale value G12 into a second corrected grayscale value G12′when the first detection signal 1DS is input.

In one embodiment, the first dot conversion unit 120 may generate thefirst corrected grayscale value G11′ and the second corrected grayscalevalue G12′, which are equal to each other.

For example, the first dot conversion unit 120 may set the average valueof the first grayscale value G11 and the second grayscale value G12 asthe first corrected grayscale value G11′ and the second correctedgrayscale value G12′. For instance, when the first grayscale value G11is “200” and the second grayscale value G12 is “100” in the second imageframe IMF2, the first corrected grayscale value G11′ for the first pixelPX1 can be set to “150” and the second corrected grayscale value G12′for the second pixel PX2 can be set to “150” in a third image frame IMF3corrected.

The data driver 12 may supply a first data voltage corresponding to thefirst corrected grayscale value G11′ to the first pixel PX1, a seconddata voltage corresponding to the second corrected grayscale value G12′to the second pixel PX2, and a third data voltage corresponding to thethird grayscale value G13 to the third pixel PX3.

Unlike the second image frame IMF2 described in association with FIG.10, since the grayscale values in the third image frame IMF3 of FIG. 12sequentially fall along the first direction DR1, the anti-aliasingeffect can be obtained even in the S-stripe structure. For instance,even if the processor 9 provides the second image frame IMF2 for theanti-aliasing font regardless of the structure of the pixel unit 14 ofthe display device 10, the second image frame IMF2 may be corrected atthe display device 10 to generate the third image frame IMF3. As such,the anti-aliasing effect can be obtained.

As another example, the first dot conversion unit 120 may set the firstcorrected grayscale value G11′ and the second corrected grayscale valueG12′ to a value obtained by adding a value obtained by applying a firstweight value wr to the first grayscale value G11 and a value obtained byapplying a second weight value wg to the second grayscale value G12.

For example, the first corrected grayscale value G11′ and the secondcorrected grayscale value G12′, which are equal to each other, can becalculated by the following Equations 10 and 11.

G11′=wr*G11+wg*G12   Equation 10

G12′=wr*G11+wg*G12   Equation 11

At this time, when the luminance of the first pixel PX1 is lower thanthe luminance of the second pixel PX2 with respect to the same grayscalevalue, the first weight value wr may be less than the second weightvalue wg. Conversely, when the luminance of the first pixel PX1 ishigher than the luminance of the second pixel PX2 with respect to thesame grayscale value, the first weight value wr may be larger than thesecond weight value wg. For instance, according to Equations 10 and 11,when setting the first corrected grayscale value G11′ and the secondcorrected grayscale value G12′, the grayscale value of a pixel having alow luminance contribution rate can be reflected as a small value andthe grayscale value of a pixel having a large luminance contributionrate can be reflected as a large value.

Reference is made to the description of FIG. 13 for the example firstand second weight values wr and wg.

FIG. 13 is a diagram for explaining a third image frame IMF3′ in whichthe second image frame is corrected differently by the grayscalecorrection unit of FIG. 11 according to an embodiment.

When the third image frame IMF3′ of FIG. 13 is compared with the thirdimage frame IMF3 of FIG. 12, the first corrected grayscale value G11′and the second corrected grayscale value G12′ may be different from eachother.

The first dot conversion unit 120 may generate the first correctedgrayscale value G11′ and the second corrected grayscale value G12′ suchthat the sum of the first grayscale value G11 and the second grayscalevalue G12 becomes equal to the sum of the first corrected grayscalevalue G11′ and the second corrected grayscale value G12′. At this time,the first corrected grayscale value G11′ and the second correctedgrayscale value G12′ may be different from each other.

For example, when the luminance of the first pixel PX1 is configured tobe lower than the luminance of the second pixel PX2 with respect to thesame grayscale value, the first corrected grayscale value G11′ may behigher than the second corrected grayscale value G12′.

Referring to the ITU-R BT.601 standard, since the degrees ofcontribution of red, green, and blue to the luminance are different fromeach other despite the same grayscale value, the following Equation 12may be established.

Y=wr*R+wg*G+wb*B, where wr=0.299, wg=0.587, wb=0.114   Equation 12

Here, Y is the luminance, R is the grayscale value of the red pixel, Gis the grayscale value of the green pixel, B is the grayscale value ofthe blue pixel, and wr, wg and wb are the weight values of therespective colors. As such, with respect to the same grayscale value,the green pixel may be the brightest and the blue pixel may be thedarkest.

Therefore, when the first pixel PX1 is the red pixel and the secondpixel PX2 is the green pixel, the luminance of the first pixel PX1 maybe lower than the luminance of the second pixel PX2 with respect to thesame grayscale value. In this case, by making the first correctedgrayscale value G11′ higher than the second corrected grayscale valueG12′, the luminance level of the first pixel PX1 and the luminance levelof the second pixel PX2 can be substantially equalized.

On the other hand, when the luminance of the second pixel PX2 isconfigured to be lower than the luminance of the first pixel PX1 withrespect to the same grayscale value, the second corrected grayscalevalue G12′ can be greater than the first corrected grayscale value G11′.

Therefore, when the first pixel PX1 is the green pixel and the secondpixel PX2 is the red pixel, the luminance of the second pixel PX2 may belower than the luminance of the first pixel PX1 with respect to the samegrayscale value. In this case, by making the second corrected grayscalevalue G12′ greater than the first corrected grayscale value G11′, theluminance level of the first pixel PX1 and the luminance level of thesecond pixel PX2 can be substantially equalized.

In another embodiment, the first dot conversion unit 120 may calculate afirst final corrected grayscale value G11_f and a second final correctedgrayscale value G12_f as shown in following Equations 13 and 14 usingthe first corrected grayscale value G11′ and the second correctedgrayscale value G12′ obtained by Equations 10 and 11.

G11_f=G11′/(wr*2)   Equation 13

G12_f=G12′/(wg*2)   Equation 14

According to Equations 13 and 14, when the luminance of the first pixelPX1 is configured to be lower than the luminance of the second pixel PX2with respect to the same grayscale value, the first final correctedgrayscale value G11_f can be greater than the second final correctedgrayscale value G12_f On the other hand, when the luminance of thesecond pixel PX2 is configured to be lower than the luminance of thefirst pixel PX1 with respect to the same grayscale value, the secondfinal corrected grayscale value G12_f can be greater than the firstfinal corrected grayscale value G11_f.

FIG. 14 is an enlarged view of the fourth to sixth dots of FIG. 8according to an embodiment.

Referring to FIGS. 8 and 14, the fifth dot DT5 b may be adjacent to thefourth dot DT4 b in the second direction DR2. The sixth dot DT6 b may beadjacent to the fourth dot DT4 b in the direction opposite to the seconddirection DR2.

In the second image frame IMF2, the fifth dot DT5 b and the fourth dotDT4 b may display a white color, which does not constitute a character,and the sixth dot DT6 b may display a black color, which constitutes thecharacter. The grayscale values of the pixels of the fifth dot DT5 b mayall be “255”, and thus, the value of the fifth dot DT5 b may be “255”.The grayscale values of the fourth pixel DT4 b, the fifth pixel DT5 b,and the sixth pixel DT6 b of the fourth dot DT4 b may all be “255”, andthus, the value of the fourth dot DT4 b may be “255”. The grayscalevalues of the pixels of the sixth dot DT6 b may all be “0”, and thus,the value of the sixth dot DT6 b may be “0”.

In the second image frame IMF2, the fourth dot DT4 b may be adjacent tothe sixth dot DT6 b corresponding to the edge of the character. Sincethe pixels PX4, PX5, and PX6 of the fourth dot DT4 b are adjacent to thesixth dot DT6 b in the second direction DR2 at the same or similar ratewith respect to the first direction DR1, there is no particular problemin displaying the second image frame IMF2 in the RGB-stripe structure.

FIG. 15 is a diagram for explaining a case where a second image frame isdisplayed without correction in the S-stripe structure according to anembodiment.

A case where the second image frame IMF2 is displayed in the pixel unit14 of the display device 10 described in association with FIG. 1 will bedescribed with reference to FIG. 15.

In the pixel unit 14, the fifth dot DT5 may be adjacent to the fourthdot DT4 in the second direction DR2 and the sixth dot DT6 may beadjacent to the fourth dot DT4 in the direction opposite to the seconddirection DR2.

The fourth dot DT4 may include the fourth pixel PX4, the fifth pixelPX5, and the sixth pixel PX6. The sixth pixel PX6 may be located in thefirst direction DR1 from the fourth pixel PX4 and the fifth pixel PX6.The fourth pixel PX4 may be located in the second direction DR2 from thefifth pixel PX5.

In the second image frame IMF2, the fifth dot DT5 and the fourth dot DT4may display a white color, which does not constitute a character, andthe sixth dot DT6 may display a black color, which constitutes thecharacter. The grayscale values of the pixels of the fifth dot DT5 mayall be “255”, and thus, the value of the fifth dot DT5 may be “255”. Thegrayscale values of the fourth pixel PX4, the fifth pixel PX5, and thesixth pixel PX6 of the fourth dot DT4 may all be “255”, and thus, thevalue of the fourth dot DT4 may be “255”. The grayscale values of thepixels of the sixth dot DT6 may all be “0”, and thus, the value of thesixth dot DT6 may be “0”.

Unlike the case described in association with FIG. 14, the distancebetween the fourth pixel PX4 and the sixth dot DT6 and the distancebetween the fifth pixel PX5 and the sixth dot DT6 may be different fromeach other. For instance, the distance between the fifth pixel PX5 andthe sixth dot DT6 may be shorter than the distance between the fourthpixel PX4 and the sixth dot DT6. Therefore, the user may view a stripepattern in which the second color C2 of the fifth pixel PX5 extends inthe first direction DR1 from the upper edge of the character (colorfringing problem).

On the other hand, referring to FIG. 8, in the fourth dot of the pixelunit 14 corresponding to the fourth dot DT4 b′, the distance between thefourth pixel and the sixth dot may be shorter than the distance betweenthe fifth pixel and the sixth dot. Therefore, the user may view a stripepattern in which the first color C1 of the fourth pixel extends in thefirst direction DR1 from the lower edge of the character.

FIG. 16 is a block diagram of a grayscale correction unit 15 b accordingto an embodiment. FIG. 17 is a diagram for explaining a fourth imageframe IMF4 in which the second image frame is corrected by the grayscalecorrection unit 15 b of FIG. 16 according to an embodiment.

Referring to FIG. 16, the grayscale correction unit 15 b may include asecond dot detection unit 210 and a second dot conversion unit 220.

The second dot detection unit 210 may output a second detection signal2DS based on grayscale values G41, G42, G43, G51, G52, G53, G61, G62,and G63 of the fourth, fifth, and sixth dots DT4, DT5, and DT6 when thefourth dot DT4 is determined as a dot adjacent to the edge of the objectincluded in the second image frame IMF2.

For example, the second dot detection unit 210 may output the seconddetection signal 2DS based on the grayscale values G41, G42, G43, G51,G52, G53, G61, G62, and G63 of the fourth, fifth, and sixth dots DT4,DT5, and DT6 when an edge value of the fourth dot DT4 is equal to orgreater than the threshold value.

According to one embodiment, the second dot detection unit 210 maycalculate the edge value of the fourth dot DT4 by applying a Prewittmask of a single column in which the second direction DR2 is the columndirection to the fourth, fifth, and sixth dots DT4, DT5, and DT6. Forexample, the Prewitt mask of the single column may correspond to thefollowing Equation 15.

$\begin{matrix}\begin{bmatrix}1 \\0 \\{- 1}\end{bmatrix} & {{Equation}\mspace{14mu} 15}\end{matrix}$

In Equation 15, “0” in the second row and the first column can bemultiplied by the value of the discrimination target dot, “1” in thefirst row and the first column can be multiplied by the value of the dotadjacent to the discrimination target dot in the second direction DR2,and “−1” in the third row and the first column can be multiplied by thevalue of a dot adjacent to the direction opposite to the seconddirection DR2 of the discrimination target dot. The sum of themultiplied values may correspond to the edge value of the discriminationtarget dot. Here, when the edge value is a negative number, it may meanthat the grayscale value falls in the second direction DR2 with thediscrimination target dot as a boundary. Also, when the edge value is apositive number, it may mean that the grayscale value rises in thesecond direction DR2 with the discrimination target dot as a boundary.

For example, a case where the fifth dot DT5 corresponds to thediscrimination target dot will be described referring to FIGS. 8, 14,and 15. A value of the fifth dot DT5 may be “255”, a value of a dotlocated in the second direction DR2 of the fifth dot DT5 may be “255”,and a value of the fourth dot DT4 may be “255”. Therefore, when thefifth dot DT5 as the discrimination target dot is applied to Equation15, the edge value of the fifth dot DT5 may become “0”.

For example, a case where the fourth dot DT4 corresponds to thediscrimination target dot will be described referring to FIGS. 8, 14,and 15. The value of the fourth dot DT4 may be “255”, the value of thefifth dot DT5 may be “255”, and the value of the sixth dot DT6 may be“0”. Therefore, when Equation 15 is applied with the fourth dot DT4 asthe discrimination target dot, the edge value of the fourth dot DT4 maybecome “255”.

In addition, for example, a case where the sixth dot DT6 corresponds tothe discrimination target dot will be described referring to FIGS. 8,14, and 15. The value of the sixth dot DT6 may be “0”, the value of thefourth dot DT4 may be “255”, and a value of a dot adjacent to the sixthdot DT6 in the direction opposite to the second direction DR2 may be“255”. Therefore, when the sixth dot DT6 as the discrimination targetdot is applied to Equation 15, the edge value of the sixth dot DT6 maybecome “0”.

According to one embodiment, the second dot detection unit 210 mayoutput the second detection signal 2DS by discriminating that thediscrimination target dot corresponds to the dot adjacent to the edge ofthe object when the edge value of the discrimination target dot is equalto or greater than the threshold value.

For example, the threshold value can be predetermined as 70% of themaximum value of the dot value. In this case, if the maximum value ofthe dot value is 255, the threshold value may become 178. Only thefourth dot DT4 among the dots DT4, DT5 and DT6 may have an absolutevalue of the edge value exceeding 178. Therefore, the second dotdetection unit 210 may output the second detection signal 2DS only tothe fourth dot DT4 among the dots DT4, DT5, and DT6.

According to one embodiment, the second detection signal 2DS may includethe sign of the edge value as information.

The mask of Equation 15 can be modified as in Equations 5, 6, 7, 8, and9. Duplicate descriptions are omitted.

When the second detection signal 2DS is input, the second dot conversionunit 220 may select one of the fourth grayscale value G41 correspondingto the fourth pixel PX4 and the fifth grayscale value G42 correspondingto the fifth pixel PX5 based on the second detection signal 2DS and maygenerate a third corrected grayscale value by decreasing a selectedgrayscale value.

As described above, the second detection signal 2DS may include the signof the edge value as information. For example, when the mask of Equation15 is used as described above, when the edge value is a negative number,it may mean that the grayscale value falls in the second direction DR2with the discrimination target dot as a boundary. In addition, when theedge value is a positive number, it may mean that the grayscale valuerises in the second direction DR2 with the discrimination target dot asa boundary.

The edge value of the fourth dot DT4 described above may be “255”, whichis a positive number. Accordingly, the second dot conversion unit 220can recognize that the boundary area between the fourth dot DT4 and thesixth dot DT6 is the edge of the object based on the second detectionsignal 2DS. In this case, the second dot conversion unit 220 may selectthe fifth grayscale value G42 corresponding to the fifth pixel PX5 andmay generate a third corrected grayscale value G42′ by decreasing thefifth grayscale value G42. When the second dot conversion unit 220generates the third corrected grayscale value G42′ by decreasing thefifth grayscale value G42, the data driver 12 may supply a data voltagecorresponding to the third corrected grayscale value G42′ to the fifthpixel PX5.

For example, the third corrected grayscale value G42′ may be obtained bydecreasing the selected fifth grayscale value G42 by 20%. The amount ofdecrease can be specified differently according to the specification ofthe display device 10.

Comparing the case where the second image frame IMF2 of FIG. 15 isapplied to the pixel unit 14 and the case where the fourth image frameIMF4 of FIG. 17 is applied to the pixel unit 14, it can be confirmedthat the color fringing problem by the fifth pixel PX5 in the S-stripstructure can be alleviated.

Referring to the dots DT4 b′, DT5 b′, and DT6 b′ in FIG. 8, the seconddot detection unit 210 may output the second detection signal 2DS havinginformation that the edge value is a negative number for the fourth tosixth dots when the discrimination target dot is the fourth dot.Therefore, the second dot conversion unit 220 can recognize that theboundary area between the fourth dot and the fifth dot is the edge ofthe object based on the second detection signal 2DS. In this case, thesecond dot conversion unit 220 may select the fourth grayscale valuecorresponding to the fourth pixel and may generate the third correctedgrayscale value by decreasing the fourth grayscale value. When thesecond dot conversion unit 220 generates the third corrected grayscalevalue by decreasing the fourth grayscale value, the data driver 12 maysupply the data voltage corresponding to the third corrected grayscalevalue to the fourth pixel.

FIG. 18 is a block diagram for explaining a grayscale correction unit 15c according to an embodiment.

The grayscale correction unit 15 c in FIG. 18 may include the grayscalecorrection unit 15 a in FIG. 11 and the grayscale correction unit 15 bin FIG. 16.

In this case, it may be a problem whether the correction by the firstdot detection unit 110 and the first dot conversion unit 120 or thecorrection by the second dot detection unit 210 and the second dotconversion unit 220 is initially performed for the second image frameIMF2.

Referring to FIGS. 7 and 8, when the processor 9 constructs the secondimage frame IMF2 using the anti-aliasing font, a sequential change ofthe grayscale values in the first direction DR1 can be confirmed.

According to one embodiment, the correction by the first dot detectionunit 110 and the first dot conversion unit 120 may be initiallyperformed so that the correction in the first direction DR1, which isthe main direction, can be initially performed. The first direction DR1may be a direction in which characters are arranged in a sentence.

In another embodiment, however, when resolution of the color fringingproblem is more important than resolution of the aliasing problem, thecorrection by the second dot detection unit 210 and the second dotconversion unit 220 may be initially performed.

FIG. 19 is an enlarged view of the seventh to tenth dots of FIG. 8according to an embodiment.

The seventh dot DT7 b may include a seventh pixel PX7 b, an eighth pixelPX8 b, and a ninth pixel PX9 b. For example, the processor 9 may providea grayscale value of “50” to the seventh pixel PX7 b, a grayscale valueof “100” to the eighth pixel PX8 b, and a grayscale value of “200” tothe ninth pixel PX9 b in the second image frame IMF2.

The eighth dot DT8 b may be adjacent to the seventh dot DT7 b in thefirst direction DR1 and may include a tenth pixel PX10 b, an eleventhpixel PX11 b, and a twelfth pixel PX12 b. For example, the processor 9may provide grayscale values of “255” to the tenth pixel PX10 b, theeleventh pixel PX11 b, and the twelfth pixel PX12 b in the second imageframe IMF2.

A ninth dot DT9 b may be adjacent to the seventh dot DT7 b in thedirection opposite to the second direction DR2 and may include athirteenth pixel PX13 b, a fourteenth pixel PX14 b, a fifteenth pixelPX15 b. For example, the processor 9 may provide a grayscale value of“50” to the thirteenth pixel PX13 b, a grayscale value of “100” to thefourteenth pixel PX14 b, and a grayscale value of “200” to the fifteenthpixel PX15 b in the second image frame IMF2.

The tenth dot DT10 b may be adjacent to the ninth dot DT9 b in the firstdirection DR1 and may include a sixteenth pixel PX16 b, a seventeenthpixel PX17 b, and an eighteenth pixel PX18 b. For example, the processor9 may provide the grayscale values of “255” to the sixteenth pixel PX16b, the seventeenth pixel PX17 b, and the eighteenth pixel PX18 b in thesecond image frame IMF2.

In the RGB-stripe structure of FIG. 19, the luminance change maysequentially occur in the first direction DR1 and the luminance may bemaintained constantly in the second direction DR2, so that theanti-aliasing effect can be exhibited.

FIG. 20 is a diagram for explaining a case where the second image frameis displayed without correction in the S-stripe structure according toan embodiment.

The seventh dot DT7 may include the seventh pixel PX7, the eighth pixelPX8, and the ninth pixel PX9. The ninth pixel PX9 may be located in thefirst direction DR1 from the seventh pixel PX7 and the eighth pixel PX8,and the seventh pixel PX7 may be located in the second direction DR2from the eighth pixel PX8.

The eighth dot DT8 may be adjacent to the seventh dot DT7 in the firstdirection DR1 and may include the tenth pixel PX10, the eleventh pixelPX11, and the twelfth pixel PX12. The twelfth pixel PX12 may be locatedin the first direction DR1 from the tenth pixel PX10 and the eleventhpixel PX11, and the tenth pixel PX10 may be located in the seconddirection DR2 from the eleventh pixel PX11.

The ninth dot DT9 may be adjacent to the seventh dot DT7 in thedirection opposite to the second direction DR2 and may include thethirteenth pixel PX13, the fourteenth pixel PX14, and the fifteenthpixel PX15. The fifteenth pixel PX15 may be located in the firstdirection DR1 from the thirteenth pixel PX13 and the fourteenth pixelPX14, and the thirteenth pixel PX13 may be located in the seconddirection DR2 from the fourteenth pixel PX14.

The tenth dot DT10 may be adjacent to the ninth dot DT9 in the firstdirection DR1 and may include the sixteenth pixel PX16, the seventeenthpixel PX17, and the eighteenth pixel PX18. The eighteenth pixel PX18 maybe located in the first direction DR1 from the sixteenth pixel PX16 andthe seventeenth pixel PX17, and the sixteenth pixel PX16 may be locatedin the second direction DR2 from the seventeenth pixel PX17.

In the S-stripe structure of FIG. 20, when the grayscale values of thesecond image frame IMF2 are applied without correction, the luminancemay change irregularly in the first direction DR1 and/or the seconddirection DR2 so that the anti-aliasing effect cannot work properly.

In addition, in the eighth pixel PX8 and the fourteenth pixel PX14 inwhich the grayscale values of “100” are provided as compared with theseventh pixel PX7 and the fourteenth pixel PX13 in which the grayscalevalues of “50” are provided, the color fringing phenomenon for thesecond color C2 may occur. This color fringing phenomenon may occur morestrongly when the luminance of the second color C2 is higher than theluminance of the first color C1 for the same grayscale value. Forexample, the second color C2 may be green and the first color C1 may bered.

FIG. 21 is a block diagram of a grayscale correction unit 15 d accordingto an embodiment. FIG. 22 is a diagram for explaining a fifth imageframe IMF5 in which the second image frame is partially corrected by thegrayscale correction unit of FIG. 21 according to an embodiment.

Referring to FIG. 21, the grayscale correction unit 15 d may include athird dot conversion unit 320. The grayscale correction unit 15 d andthe third dot conversion unit 320 may refer to the same components.

Unlike the other embodiments, the grayscale correction unit 15 d may notinclude a separate dot detection unit. For example, the grayscalecorrection unit 15 d may perform grayscale correction on all the dotswithout the process for detecting the edge dot. However, the grayscalecorrection may not be applied to some outermost dots to which thefollowing Equations cannot be applied.

The grayscale correction unit 15 d may generate corrected grayscalevalues G71′, G72′, and G73′ for colors C1, C2, and C3, respectively, ofthe seventh dot DT7 based on grayscale values G71, G72, G73, G81, G82,G83, G91, G92, G93, G101, G102, and G103 for the same colors of theeighth, ninth, and tenth dots DT8, DT9, and DT10.

The grayscale correction unit 15 d may generate a fourth correctedgrayscale value G71′ for the first color C1 based on the grayscalevalues G71, G81, G91, and G101 of the seventh pixel PX7, the tenth pixelPX10, the thirteenth pixel PX13, and the sixteenth pixel PX16.

The grayscale correction unit 15 d may generate a fifth correctedgrayscale value G72′ for the second color C2 based on the grayscalevalues G72, G82, G92, and G102 of the eighth pixel PX8, the eleventhpixel PX11, the fourteenth pixel PX14, and the seventeenth pixel PX17.In addition, the grayscale correction unit 15 d may generate a sixthcorrected grayscale value G73′ for the third color C3 based on thegrayscale values G73, G83, G93, and G103 of the ninth pixel PX9, thetwelfth pixel PX12, the fifteenth pixel PX15, and the eighteenth pixelPX18.

The data driver 12 may supply the data voltage corresponding to thefourth corrected grayscale value G71′ to the seventh pixel PX7, the datavoltage corresponding to the fifth corrected grayscale value G72′ to theeighth pixel PX8, and the data voltage corresponding to the sixthcorrected grayscale value G73′ to the ninth pixel PX9.

For example, the grayscale correction unit 15 d may generate the fourth,fifth, and sixth corrected grayscale values G71′, G72′, and G73′ for theseventh dot DT7 based on the following Equation 16.

$\begin{matrix}\begin{bmatrix}{F\; 1} & {F\; 2} \\{F\; 3} & {F\; 4}\end{bmatrix} & {{Equation}\mspace{14mu} 16}\end{matrix}$

Here, F1 is a weight value to be multiplied by each of the pixels PX7,PX8, and PX9 of the seventh dot DT7, F2 is a weight value to bemultiplied by each of the pixels PX10, PX11, and PX12 of the eighth dotDT8, F3 is a weight value to be multiplied by each of the pixels PX13,PX14, and PX15 of the ninth dot DT9, and F4 is a weight value to bemultiplied by each of the pixels PX16, PX17, and PX18 of the tenth dotDT10.

According to one embodiment, in Equation 16, the magnitude of F1 may begreater than those of F2, F3, and F4. For example, the self-grayscaleratio may be relatively large. Therefore, F1 (which is the weight valuefor the grayscale value G71 of the seventh pixel PX7) may be the largestin generating the fourth corrected grayscale value G71′, F1 (which isthe weight value for the grayscale value G72 of the eighth pixel PX8)may be the largest in generating the fifth corrected grayscale valueG72′, and F1 (which is the weight value for the grayscale value G73 ofthe ninth pixel PX9) may be the largest in generating the sixthcorrected grayscale value G73′.

According to one embodiment, the value obtained by adding F1, F2, F3,and F4 in Equation 16 may be 1. At this time, F1, F2, F3, and F4 can bevariably adjusted to about 20% depending on the product. For example, F1may be set to 0.625, F2 may be set to 0.125, F3 may be set to 0.125, andF4 may be set to 0.125. In addition, F1 may be a value in a range from0.5 to 0.75, F2 may be a value in a range from 0.1 to 0.15, F3 may be avalue in a range from 0.1 to 0.15, and F4 may be a value in a range from0.1 to 0.15, depending on the product.

Those skilled in the art will be able to determine the values of F1, F2,F3, and F4 that are appropriate for the product by appropriatelyadjusting the example values.

For example, the fourth corrected grayscale value G71′ may be calculatedas shown in the following Equation 17.

0.625*50+0.125*255+0.125*50+0.125*255=101.25   Equation 17

Here, when digits after the decimal point are discarded, the fourthcorrected grayscale value G71′ may be “101”.

For example, the fifth corrected grayscale value G72′ may be calculatedas shown in the following Equation 18.

0.625*100+0.125*255+0.125*100+0.125*255=138.75   Equation 18

Here, when digits after the decimal point are discarded, the fifthcorrected grayscale value G72′ may be “138”.

For example, the sixth corrected grayscale value G73′ can be calculatedas shown in the following Equation 19.

0.625*200+0.125*255+0.125*200+0.125*255=213.75   Equation 19

Here, when digits after the decimal point are discarded, the sixthcorrected grayscale value G73′ may be “213”.

It can be seen that the calculated fourth, fifth, and sixth correctedgrayscale values G71′, G72′, and G73′ have a smaller difference than thepre-corrected grayscale values G71, G72, and G73. Therefore, the colorfringing problem that occurs in FIG. 20 can be mitigated.

In addition, it can be seen that the calculated fourth, fifth, and sixthcorrected grayscale values G71′, G72′, and G73′ are corrected in thehigh grayscale direction as compared with the pre-corrected grayscalevalues G71, G72, and G73. Since the human eyes are less sensitive to thechange in the high grayscale than the change in the low grayscale, thecolor fringing problem that occurs in FIG. 20 can be further mitigated.

FIG. 22 shows a fifth partial image frame IMF5 p to which the correctedgrayscale values G71′, G72′, and G73′ are applied to the seventh dotDT7, which is a part of the second image frame IMF2. The same process asdescribed above can be performed by the grayscale correction unit 15 dfor the other dots DT8, DT9, and DT10. The data processed by thegrayscale correction unit 15 d may depend on the data of the secondimage frame IMF2 provided by the processor 9 and may be independent ofthe data of the fifth partial image frame IMF5 p already processed.

According to one embodiment, the grayscale correction unit 15 d may setF3 and F4 in Equation 16 to 0 in order to perform correction on thefirst direction DR1. For example, F1=0.75, F2=0.25, F3=0, and F4=0 maybe satisfied.

According to another embodiment, the grayscale correction unit 15 d mayset F2 and F4 in Equation 16 to 0 in order to perform correction on thesecond direction DR2. For example, F1=0.75, F2=0, F3=0.25, and F4=0 maybe satisfied.

FIG. 23 is a diagram for explaining a case where embodiments are appliedto the S-stripe structure which is different from FIGS. 1 and 4.

Referring to FIG. 23, a first dot nDT may include a first pixel nPX1, asecond pixel nPX2, and a third pixel nPX3. The first pixel nPX1 may belocated in the first direction DR1 from the second pixel nPX2 and thefirst pixel nPX1 and the second pixel nPX2 may be located in the seconddirection DR2 from the third pixel nPX3.

For instance, the first dot nDT of FIG. 23 may be tilted by 90 degreeswith respect to the first dot DT1 of FIG. 1.

The case of the embodiment described in association with FIG. 23 mayalso include the second dot adjacent to the first dot nDT in the firstdirection DR1 and the third dot adjacent to the first dot nDT in thedirection opposite to the first direction DR1.

All the embodiments that can be applied to the first dot DT1 of FIG. 1can be applied to the first dot nDT of FIG. 23.

For example, when the first dot nDT is determined as the edge of theobject included in the image frame based on the grayscale values of thefirst to third dots, the grayscale correction unit may generate thefirst corrected grayscale value and the second corrected grayscale valuebased on the first grayscale value corresponding to the first pixel nPX1and the second grayscale value corresponding to the second pixel nPX2.

The grayscale correction unit may include a first dot detection unit foroutputting a first detection signal when the edge value of the first dotnDT calculated based on the grayscale values of the first to third dotsis equal to or greater than a threshold value.

In addition, the grayscale correction unit may include a first dotconversion unit. The first dot conversion unit may convert the firstgrayscale value into the first corrected grayscale value and may convertthe second grayscale value into the second corrected grayscale valuewhen the first detection signal is input. The first corrected grayscalevalue and the second corrected grayscale value may be equal to eachother.

On the other hand, the grayscale correction unit may include a first dotconversion unit. The first dot conversion unit may convert the firstgrayscale value into the first corrected grayscale value and may convertthe second grayscale value into the second corrected grayscale valuewhen the first detection signal is input. The sum of the first grayscalevalue and the second grayscale value may be equal to the sum of thefirst corrected grayscale value and the second corrected grayscalevalue.

The case of the embodiment described in association with FIG. 23 mayinclude the fifth dot adjacent to the fourth dot in the second directionDR2 and the sixth dot adjacent to the fourth dot in the directionopposite to the second direction DR2. The fourth dot may include thefourth pixel, the fifth pixel, and the sixth pixel. The sixth pixel maybe located in the first direction DR1 from the fourth pixel and thefifth pixel and the fourth pixel may be located in the second directionDR2 from the fifth pixel.

The grayscale correction unit may include a second dot detection unitfor outputting the second detection signal when the fourth dot isdetermined as a dot adjacent to the edge of the object included in theimage frame based on the grayscale values for the fourth to sixth dots.

In addition, the grayscale correction unit may include a second dotconversion unit for generating the third corrected grayscale value. Thesecond dot conversion unit may select one of the fourth grayscale valuecorresponding to the fourth pixel and the fifth grayscale valuecorresponding to the fifth pixel based on the second detection signalwhen the second detection signal is input and may generate the thirdcorrected grayscale value by decreasing the selected grayscale value.

At this time, the first corrected grayscale value and the secondcorrected grayscale value may be equal to each other.

FIGS. 24 and 25 are diagrams for explaining a grayscale correction unitaccording to an embodiment.

Referring to FIG. 24, among a plurality of dots, a target dot DT22 c andneighboring dots DT11 c, DT12 c, DT13 c, DT21 c, DT23 c, DT31 c, DT32 c,and DT33 c are shown as an example.

The neighboring dots DT11 c to DT21 c and DT23 c to DT33 c may be dotsadjacent to the target dot DT22 c. For example, other dots may not bedisposed between the target dot DT22 c and the neighboring dots DT11 cto DT21 c and DT23 c to DT33 c.

In FIG. 24, each of the dots DT11 c to DT33 c is shown to have anS-stripe structure. However, even if each of the dots DT11 c to DT33 chas the structure of FIGS. 23 and 31 to 34, the RGB stripe structure, orthe like, embodiments described below may be applied.

The dots DT11 c to DT33 c may be arranged in a matrix form in which afirst direction DR1 is a row direction and a second direction DR2 is acolumn direction. Each of the dots DT11 c to DT33 c may include a firstpixel of a first color C1, a second pixel of a second color C2, and athird pixel of a third color C3.

The dot DT11 c may include a first pixel PX111, a second pixel PX112,and a third pixel PX113. The third pixel PX113 may be positioned in thefirst direction DR1 from the first pixel PX111 and the second pixelPX112, and the first pixel PX111 may be positioned in the seconddirection DR2 from the second pixel PX112.

The dot DT12 c may include a first pixel PX121, a second pixel PX122,and a third pixel PX123. The third pixel PX123 may be positioned in thefirst direction DR1 from the first pixel PX121 and the second pixelPX122, and the first pixel PX121 may be positioned in the seconddirection DR2 from the second pixel PX122.

The dot DT13 c may include a first pixel PX131, a second pixel PX132,and a third pixel PX133. The third pixel PX133 may be positioned in thefirst direction DR1 from the first pixel PX131 and the second pixelPX132, and the first pixel PX131 may be positioned in the seconddirection DR2 from the second pixel PX132.

The dot DT21 c may include a first pixel PX211, a second pixel PX212,and a third pixel PX213. The third pixel PX213 may be positioned in thefirst direction DR1 from the first pixel PX211 and the second pixelPX212, and the first pixel PX211 may be positioned in the seconddirection DR2 from the second pixel PX212.

The dot DT22 c may include a first pixel PX221, a second pixel PX222,and a third pixel PX223. The third pixel PX223 may be positioned in thefirst direction DR1 from the first pixel PX221 and the second pixelPX222, and the first pixel PX221 may be positioned in the seconddirection DR2 from the second pixel PX222.

The dot DT23 c may include a first pixel PX231, a second pixel PX232,and a third pixel PX233. The third pixel PX233 may be positioned in thefirst direction DR1 from the first pixel PX231 and the second pixelPX232, and the first pixel PX231 may be positioned in the seconddirection DR2 from the second pixel PX232.

The dot DT31 c may include a first pixel PX311, a second pixel PX312,and a third pixel PX313. The third pixel PX313 may be positioned in thefirst direction DR1 from the first pixel PX311 and the second pixelPX312, and the first pixel PX311 may be positioned in the seconddirection DR2 from the second pixel PX312.

The dot DT32 c may include a first pixel PX321, a second pixel PX322,and a third pixel PX323. The third pixel PX323 may be positioned in thefirst direction DR1 from the first pixel PX321 and the second pixelPX322, and the first pixel PX321 may be positioned in the seconddirection DR2 from the second pixel PX322.

The dot DT33 c may include a first pixel PX331, a second pixel PX332,and a third pixel PX333. The third pixel PX333 may be positioned in thefirst direction DR1 from the first pixel PX331 and the second pixelPX332, and the first pixel PX331 may be positioned in the seconddirection DR2 from the second pixel PX332.

Referring to FIG. 25, a grayscale correction unit 15 e may include afourth dot conversion unit 420. Here, the grayscale correction unit 15 eand the fourth dot conversion unit 420 may refer to the same component.

The grayscale correction unit 15 e may determine a target dot to becorrected, and determine neighboring dots adjacent to the target dot.For example, the grayscale correction unit 15 e may sequentiallydetermine dots constituting the pixel unit 14 or 14′ as the target dot.Here, a case in which the dot DT22 c is determined as the target dotwill be described as an example.

The grayscale correction unit 15 e (or the fourth dot conversion unit420) may generate corrected grayscale values G221′, G222′, and G223′ forthe target dot DT22 c by applying weights to grayscale values G221,G222, and G223 of the target dot DT22 c and grayscale values G111, G112,G113, G121, G122, G123, G131, G132, G133, G211, G212, G213, G231, G232,G233, G311, G312, G313, G321, G322, G323, G331, G332, and G333 of theneighboring dots DT11 c to DT21 c and DT23 c to DT33 c of the target dotDT22 c among the dots.

For example, the weights may be stored in advance in the form of alook-up table or the like.

$\begin{matrix}{{FMTX} = \begin{bmatrix}{F\; 11} & {F\; 12} & {F\; 13} \\{F\; 21} & {F\; 22} & {F\; 23} \\{F\; 31} & {F\; 32} & {F\; 33}\end{bmatrix}} & {{Equation}\mspace{14mu} 20}\end{matrix}$

Referring to Equation 20, FMTX may include weights F11, F12, F13, F21,F22, F23, F31, F32, and F33. The weights F11, F12, F13, F21, F22, F23,F31, F32, and F33 may be applied to corresponding dots DT11 c, DT12 c,DT13 c, DT21 c, DT22 c, DT23 c, DT31 c, DT32 c, and DT33 c,respectively. FMTX is only a means to easily show the mapping betweenthe weights F11 to F33 and the dots DT11 c to DT33 c, and does not meanthat the weights F11 to F33 must be stored as data in matrix form.

The fourth dot conversion unit 420 may generate a first correctedgrayscale value G221′ for the first pixel PX221 of the target dot DT22 cby applying the weights F11 to F33 to grayscale values G111, G121, G131,G211, G221, G231, G311, G321, and G331 of first pixels PX111, PX121,PX131, PX211, PX221, PX231, PX311, PX321, and PX331 of the target dotDT22 c and the neighboring dots DT11 c to DT21 c and DT23 c to DT33 c.

In addition, the fourth dot conversion unit 420 may generate a secondcorrected grayscale value G222′ for the second pixel PX222 of the targetdot DT22 c by applying the weights F11 to F33 to grayscale values G112,G122, G132, G212, G222, G232, G312, G322, and G332 of second pixelsPX112, PX122, PX132, PX212, PX222, PX232, PX312, PX322, and PX332 of thetarget dot DT22 c and the neighboring dots DT11 c to DT21 c and DT23 cto DT33 c.

In addition, the fourth dot conversion unit 420 may generate a thirdcorrected grayscale value G223′ for the third pixel PX223 of the targetdot DT22 c by applying the weights F11 to F33 to grayscale values G113,G123, G133, G213, G223, G233, G313, G323, and G333 of third pixelsPX113, PX123, PX133, PX213, PX223, PX233, PX313, PX323, and PX333 of thetarget dot DT22 c and the neighboring dots DT11 c to DT21 c and DT23 cto DT33 c.

According to an embodiment, in Equation 20, the magnitude of a weightF22 for the target dot DT22 c may be greater than other weights F11 toF21 and F23 to F33. For instance, a self-grayscale ratio may be large.

According to an embodiment, in Equation 20, the sum of the weights F11to F33 may be 1. In this case, depending on a product, the weights F11to F33 may be variably adjusted within a range of 0% to 400%. Forexample, the weight F11 may be set to 0.0625, the weight F12 may be setto 0.125, the weight F13 may be set to 0.0625, the weight F21 may be setto 0.125, the weight F22 may be set to 0.25, the weight F23 may be setto 0.125, the weight F31 may be set to 0.0625, the weight F32 may be setto 0.125, and the weight F33 may be set to 0.0625.

Since an effect of alleviating the color fringing problem by the fourthdot conversion unit 420 may be similar to the effect of the third dotconversion unit 320 of FIG. 21, duplicate descriptions will be omitted.

FIGS. 26 and 27 are diagrams for explaining a grayscale correction unitaccording to an embodiment.

Referring to FIG. 26, a grayscale correction unit 15 f may be differentfrom the grayscale correction unit 15 e described in association withFIG. 25 in that it further includes a weight generation unit 430. Indescription of the grayscale correction unit 15 f, contents overlappingthe description of the grayscale correction unit 15 e will be omitted.

The grayscale correction unit 15 f may determine weights FMTX based onthe grayscale values G221, G222, and G223 of the target dot DT22 c. Inparticular, the weight generation unit 430 may calculate a saturationvalue SV by comparing a first grayscale value G221 for the first pixelPX221, a second grayscale value G222 for the second pixel PX222, and athird grayscale value G223 for the third pixel PX223 of the target dotDT22 c, and generate the weights FMTX based on the saturation value SV(refer to FIG. 27). The weight generation unit 430 may not use grayscalevalues G111 to G213 and G231 to G333 of neighboring dots DT11 c to DT21c and DT23 c to DT33 c when calculating the saturation value SV. Thesaturation value SV may be calculated with reference to Equation 21below.

SV=(max(R, G, B)−min(R, G, B))/max(R, G, B)   Equation 21

Here, SV may be the saturation value SV and may have a range of 0 to 1.It is noted that max(R, G, B) may mean a maximum value among the first,second, and third grayscale values G221, G222, and G223 of the targetdot DT22 c. Also, min(R, G, B) may mean a minimum value among the first,second, and third grayscale values G221, G222, and G223 of the targetdot DT22 c.

When the saturation value SV is a maximum value (for example, 1), atleast one of the first, second, and third grayscale values G221, G222,and G223 of the target dot DT22 c may be 0. In this case, the target dotDT22 c may be a case of purely emitting light in the first color, thesecond color, or the third color, or may be a case of emitting light ina combination of two colors. Referring to FIG. 27, when the saturationvalue SV is a maximum value Smax, the weight F22 for the target dot DT22c may be 1, and the weights F11 to F21 and F23 to F33 for theneighboring dots DT11 c to DT21 c and DT23 c to DT33 c may be 0. Forinstance, when the saturation value SV is the maximum value Smax, thecolor fringing phenomenon may not appear or may hardly appear.Therefore, the corrected grayscale values G221′, G222′, and G223′ of thetarget dot DT22 c may be set to be the same as the grayscale valuesG221, G222, and G223.

When the saturation value SV is a reference value Sref smaller than themaximum value Smax, the first grayscale value G221, the second grayscalevalue G222, and the third grayscale value G223 of the target dot DT22 cmay all be greater than 0. For example, in this case, as a generaldisplay state, the color fringing phenomenon may appear. When thesaturation value SV is the reference value Sref, weights F11 r, F12 r,F13 r, F21 r, F22 r, F23 r, F31 r, F32 r, and F33 r for the target dotDT22 c and the neighboring dots DT11 c to DT21 c and DT23 c to DT33 cmay both be greater than 0 and less than 1. When the saturation value SVis the reference value Sref, the weight F22 r of the target dot DT22 cmay be greater than the weights for the neighboring dots DT11 c to DT21c and DT23 c to DT33 c. As described with reference to FIG. 25, theweight F11 r may be set to 0.0625, the weight F12 r may be set to 0.125,the weight F13 r may be set to 0.0625, the weight F21 r may be set to0.125, the weight F22 r may be set to 0.25, the weight F23 r may be setto 0.125, the weight F31 r may be set to 0.0625, the weight F32 r may beset to 0.125, and the weight F33 r may be set to 0.0625. In this case, afilter may be applied in the same manner as in the embodiment of FIG. 25so that the color fringing phenomenon may be improved.

When the saturation value SV is smaller than the maximum value Smax andgreater than the reference value Sref, the weights F11 to F33 may begradually set. For example, as the saturation value SV graduallydecreases from the maximum value Smax to the reference value Sref, theweights F11 to F21 and F23 to F33 of the neighboring dots DT11 c to DT21c and DT23 c to DT33 c may gradually increase. For example, the weightF11 may gradually increase from 0 to F11 r (for example, 0.0625).However, the gradients of the weights F11 to F21 and F23 to F33 need notincrease uniformly. In some case, even if the saturation value SV isdecreased, the weights F11 to F21 and F23 to F33 may remain the same.

Meanwhile, as the saturation value SV gradually decreases from themaximum value Smax to the reference value Sref, the weight F22 for thetarget dot DT22 c may gradually decrease. For example, the weight F22may gradually decrease from 1 to F22 r (for example, 0.25). However, thegradient of the weight F22 need not decrease uniformly. In some cases,even if the saturation value SV is decreased, the weight F22 may remainthe same (refer to FIGS. 28 to 30).

When the saturation value SV is a minimum value Smin smaller than thereference value Sref, weights F11 u, F12 u, F13 u, F21 u, F22 u, F23 u,F31 u, F32 u, and F33 u may be variously set.

FIGS. 28 to 30 are diagrams for explaining variously set weights when asaturation value is a minimum value according to various embodiments.

Referring to FIGS. 28 to 30, a graph is shown as an example in which thehorizontal axis represents the magnitude of the saturation value SV andthe vertical axis represents the magnitude of the weight F22. Threegraphs may have the same shape when the saturation value SV is greaterthan the reference value Sref. However, when the saturation value SV issmaller than the reference value Sref, in particular, when thesaturation value SV is the minimum value Smin, the three graphs may havedifferent shapes.

When the saturation value SV is the minimum value Smin, the grayscalevalues G221, G222, and G223 of the first to third colors C1, C2, and C3of the target dot DT22 c may be the same, and an achromatic color may bedisplayed. In this case, the display device 10 may need to improve thecolor fringing problem depending on the product, or may not need toimprove the color fringing problem.

For example, in the case of displaying an achromatic color, the displaydevice 10 may not need to improve the color fringing problem. Referringto FIG. 28, when the saturation value SV is the minimum value Smin, theweights F11 u to F33 u of the target dot DT22 c and the neighboring dotsDT11 c to DT21 c and DT23 c to DT33 c may be the same as the weightswhen the saturation value SV is the maximum value Smax. For example, theweight F11 u may be set to 0, the weight F12 u may be set to 0, theweight F13 u may be set to 0, the weight F21 u may be set to 0, theweight F22 u may be set to 1, the weight F23 u may be set to 0, theweight F31 u may be set to 0, the weight F32 u may be set to 0, and theweight F33 u may be set to 0.

For example, in the case of displaying an achromatic color, the displaydevice 10 may need to improve the color fringing problem. Referring toFIG. 29, when the saturation value SV is the minimum value Smin, theweights F11 u to F33 u of the target dot DT22 c and the neighboring dotsDT11 c to DT21 c and DT23 c to DT33 c may be intermediate values betweenthe weights F11 r to F33 r when the saturation value SV is the referencevalue Sref and the weights when the saturation value SV is the maximumvalue Smax. Meanwhile, referring to FIG. 30, when the saturation valueSV is the minimum value Smin, the weights F11 u to F33 u of the targetdot DT22 c and the neighboring dots DT11 c to DT21 c and DT23 c to DT33may be the same as the weights F11 r to F33 r when the saturation valueSV is the reference value Sref.

FIGS. 31 to 34 are diagrams for explaining structures of dots accordingto various embodiments.

Referring to FIG. 31, dots DT11 d, DT12 d, DT21 d, and DT22 d may besimilar to the dots DT7, DT8, DT9, and DT10 described in associationwith FIG. 20 except for pixels of the third color C3. The pixels of thethird color C3 described in association with FIG. 20 may have the sameshape and position within all the dots DT7, DT8, DT9, and DT10.Meanwhile, in FIG. 31, a distance between pixels of the third color C3of the dots DT11 d and DT21 d in the second direction DR2 may bedifferent from a distance between pixels of the third color C3 of thedots DT12 d and DT22 d in the second direction DR2. For example, thedistance between the pixels of the third color C3 of the dots DT11 d andDT21 d in the second direction DR2 may be shorter than the distancebetween the pixels of the third color C3 of the dots DT12 d and DT22 din the second direction DR2. The above-described embodiments may also beapplied to the case of FIG. 31.

Referring to FIG. 32, each of dots DT11 e, DT12 e, DT21 e, and DT22 emay include a pixel of the first color C1 having a rhombus shape, apixel of the second color C2, and a pixel of the third color C3 having ahexagonal shape. The pixel of the first color C1 may be positioned inthe first direction DR1 from the pixel of the second color C2, and thepixel of the third color C3 may be positioned in the second directionDR2 from the pixels of the first color C1 and the second color C2. Theabove-described embodiments may also be applied to the case of FIG. 32.

Referring to FIG. 33, in adjacent dots among dots DT11 f, DT12 f, DT13f, DT14 f, DT21 f, DT22 f, DT23 f, and DT24 f, pixels of the third colorC3 may share an emission layer. For example, pixels of the third colorC3 of the dots DT11 f and DT12 f may share an emission layer. Forexample, the pixels of the third color C3 may have different pixelcircuits and different anodes, but may have a common emission layer madeof an organic deposition material. The emission layer shared by thepixels of the third color C3 may have a rhombus shape. Meanwhile, thepixel of the first color C1 and the pixel of the second color C2 mayhave an emission layer having a triangular shape. The above-describedembodiments may also be applied to the case of FIG. 33.

Referring to FIG. 34, in adjacent dots among dots DT11 g, DT12 g, DT13g, DT14 g, DT21 g, DT22 g, DT23 g, and DT24 g, pixels of the third colorC3 may share an emission layer. For example, pixels of the third colorC3 of the dots DT11 g and DT12 g may share an emission layer. Forexample, the pixels of the third color C3 may have different pixelcircuits and different anodes, but may have a common emission layer madeof an organic deposition material. The emission layer shared by thepixels of the third color C3 may have a cross shape. Meanwhile, thepixel of the first color C1 and the pixel of the second color C2 mayhave an emission layer having a rectangular shape. The above-describedembodiments may also be applied to the case of FIG. 34.

The display device according to various embodiments can display an imageframe in which aliasing is relaxed for various pixel arrangementstructures.

Although certain embodiments and implementations have been describedherein, other embodiments and modifications will be apparent from thisdescription. Accordingly, the inventive concepts are not limited to suchembodiments, but rather to the broader scope of the accompanying claimsand various obvious modifications and equivalent arrangements as wouldbe apparent to one of ordinary skill in the art.

What is claimed is:
 1. A display device comprising: dots, each dot amongthe dots comprising a first pixel of a first color, a second pixel of asecond color, and a third pixel of a third color; and a grayscalecorrection unit configured to generate corrected grayscale values for atarget dot via application of weights to grayscale values of the targetdot and grayscale values of neighboring dots of the target dot among thedots, wherein the grayscale correction unit is configured to determinethe weights based on the grayscale values of the target dot.
 2. Thedisplay device of claim 1, wherein the grayscale correction unitcomprises a dot conversion unit configured to generate a first correctedgrayscale value for the first pixel of the target dot via application ofthe weights to grayscale values of first pixels of the target dot andthe neighboring dots.
 3. The display device of claim 2, wherein the dotconversion unit is configured to generate a second corrected grayscalevalue for the second pixel of the target dot via application of theweights to grayscale values of second pixels of the target dot and theneighboring dots.
 4. The display device of claim 3, wherein the dotconversion unit is configured to generate a third corrected grayscalevalue for the third pixel of the target dot via application of theweights to grayscale values of third pixels of the target dot and theneighboring dots.
 5. The display device of claim 1, wherein: thegrayscale correction unit comprises a weight generation unit; and theweight generation unit is configured to: determine a saturation valuevia comparison of a first grayscale value for the first pixel, a secondgrayscale value for the second pixel, and a third grayscale value forthe third pixel of the target dot; and generate the weights based on thesaturation value.
 6. The display device of claim 5, wherein the weightgeneration unit does not use the grayscale values of the neighboringdots in the determination of the saturation value.
 7. The display deviceof claim 5, wherein, in response to the saturation value being a maximumvalue, at least one of the first grayscale value, the second grayscalevalue, and the third grayscale value of the target dot is
 0. 8. Thedisplay device of claim 7, wherein, in response to the saturation valuebeing the maximum value, a weight for the target dot is 1, and weightsfor the neighboring dots are
 0. 9. The display device of claim 8,wherein, in response to the saturation value being a reference valuesmaller than the maximum value, the first grayscale value, the secondgrayscale value, and the third grayscale value of the target dot are allgreater than
 0. 10. The display device of claim 9, wherein, in responseto the saturation value being the reference value, the weights for thetarget dot and the neighboring dots are both greater than 0 and lessthan
 1. 11. The display device of claim 10, wherein, in response to thesaturation value being the reference value, the weight for the targetdot is greater than the weights for the neighboring dots.
 12. Thedisplay device of claim 11, wherein, in response to the saturation valuebeing a minimum value smaller than the reference value, the weights forthe target dot and the neighboring dots are the same as the weights whenthe saturation value is the maximum value.
 13. The display device ofclaim 11, wherein, in response to the saturation value being the minimumvalue smaller than the reference value, the weights for the target dotand the neighboring dots are intermediate values between the weightswhen the saturation value is the reference value and the weights whenthe saturation value is the maximum value.
 14. The display device ofclaim 11, wherein, in response to the saturation value being the minimumvalue smaller than the reference value, the weights for the target dotand the neighboring dots are the same as the weights when the saturationvalue is the reference value.
 15. A method of driving a display device,the method comprising: receiving grayscale values of a target dot andgrayscale values of neighboring dots of the target dot among dots of thedisplay device, each dot among the dots comprising a first pixel of afirst color, a second pixel of a second color, and a third pixel of athird color; determining weights based on the grayscale values of thetarget dot; and generating corrected grayscale values for the target dotby applying the weights to the grayscale values of the target dot andthe grayscale values of the neighboring dots of the target dot.
 16. Themethod of claim 15, wherein, in determining the weights, a saturationvalue is determined by comparing a first grayscale value for the firstpixel, a second grayscale value for the second pixel, and a thirdgrayscale value for the third pixel of the target dot, and the weightsare determined based on the saturation value.
 17. The method of claim16, wherein the grayscale values of the neighboring dots are not usedwhen determining the saturation value.
 18. The method of claim 16,wherein, in response to the saturation value being a maximum value, atleast one of the first grayscale value, the second grayscale value, andthe third grayscale value of the target dot is 0, a weight for thetarget dot is 1, and weights for the neighboring dots are
 0. 19. Themethod of claim 18, wherein, in response to the saturation value being areference value smaller than the maximum value, the first grayscalevalue, the second grayscale value, and the third grayscale value of thetarget dot are all greater than 0, and the weights for the target dotand the neighboring dots are both greater than 0 and less than
 1. 20.The method of claim 19, wherein, in response to the saturation valuebeing a minimum value smaller than the reference value, the weights forthe target dot and the neighboring dots are the same as the weights whenthe saturation value is the maximum value.